Chunbing Yang

Three dimensional (3D) textiles are preferable reinforcing materials for composites with lightweight and higher mechanical properties. In this study, a 3D woven flax fiber reinforced PLA composite with better flexural and tensile properties was developed. Four hybrid yarns with varied PLA contents were prepared as warp, weft and z‐yarns to weave the 3D preform and then changed to composites through compression molding technology without additional fillers and matrixes. The composite's flexural and tensile properties were studied and an optimum value of 78.0 and 140.0 MPa respectively were found. Stress strain properties were also discussed which implies the flexural elongation is higher than those of tensile values. The microstructure was analyzed using optical microscope and SEM equipment's showed composites with higher PLA content were more brittle due to the PLA inimitable behavior. The thermal properties of the 3D composites made with different Flax/PLA combinations have closer and comparable values. One way ANOVA statistical analysis was done to show the significancy of PLA /Flax mass ratio, which has a significant effect on composite's properties. This study could bring a novel procedural approach for an advanced 3D woven composites for load bearing applications.Highlights: 3D woven flax /PLA composite was developed using Flax/PLA hybrid yarns Tensile and flexural properties were studied Flexural strength increases with PLA, but, slightly lower in its strain PLA/Flax mass ratio has a significant effect on composite's properties The mechanical strengths were improved compared to the related findings

Three‐dimensional woven spacer composites (3DWSCs) with lightweight and excellent mechanical properties have promising application in communication, transportation, aerospace and other fields. However, traditional single‐layer 3DWSCs exhibit insufficient strength, especially when dealing with high thickness, as the pile yarns tend to buckle. In this study, inspired by the structural features of the Thalia dealbata, 3D woven integrated double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated. Innovative integrated double‐layer structure design effectively improves the performance and failure mode of 3DWSCs under bending loads. Compared to single‐layer 3DWSCs, the resulting double‐layer 3DWSCs exhibited a 41.79% increase in peak bending load, a 46.85% increase in bending stiffness, and a 99.38% increase in energy absorption. In addition, the double‐layer 3DWSCs showed a low density of 0.52–0.55 g/cm³. This work introduces bioinspired double‐layer 3DWSCs with characteristics of lightweight and superior bending performance, potentially offering novel ideas for the design of high‐performance composites.Highlights: Inspired by the structural features of the Thalia dealbata, a 3D integrated woven double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated. 3D woven double‐layer spacer composites are lightweight (0.52–0.55 g/cm³) and can effectively improve the bending properties of single‐layer structures. Based on the analysis of the fracture morphology, the significant improvement of the fracture pattern of the single‐layer structure by the double‐layer structure is effectively demonstrated. This study introduces novel design strategies for multi‐layer lightweight composite materials and holds broad applications.